Large amounts of data are transmitted across networks in contemporary telecommunications systems. The data may be routed through data centers that include telecommunications hardware. The data center may include hundreds or thousands of routers and/or switches for enabling data transmission between devices across the network. These routers and switches are typically implemented in a compact form factor that enables a data center to easily scale the capacity of the network by adding additional hardware. For example, a data center may include a plurality of chassis on one or more racks. The chassis is a frame or housing that allows easy mounting of different circuit components. A power supply and backplane may be mounted to the chassis and different line cards may be inserted into connectors on the backplane. The backplane routes power from the power supply to each of the line cards and routes data from one line card to another line card. Line cards provide access to the network for one or more different interfaces (e.g., POTS, ISDN, VDSL, etc.).
A typical backplane is comprised of thousands of individual channels (i.e., serial links), which may be realized as copper traces on a large, multi-layer printed circuit board (PCB). Data may be transmitted across a channel using serial communication. A device known as a Serializer/Deserializer (SerDes), which currently operates at data rates of 25 Gbps or higher, may be included in one or more integrated circuits on each line card and used for routing high-speed data on the backplane. A SerDes device may include a serial-line receiver, a serial-link transmitter, or a serial-link transceiver. The SerDes device may receive data symbols for transmission and convert the data symbols into a transmission signal that is sent over the channel via a high speed transmitter. A different SerDes device also coupled to the channel may receive the transmission signal at a receiver and convert the transmission signal back into the data symbols. Data symbols may be single bits (i.e., logic high or logic low) encoded as particular voltage levels or transitions of voltage levels, or data symbols may be multiple bits, such as in PAM encoding, 8b/10b encoding, and the like. Current SerDes devices are capable of operating at a bit error rate (BER) of less than 10−15. Each integrated circuit included on the line card typically incorporates many high-speed serial-link transmitters and receivers that can operate concurrently on a backplane.
The dense network of channels on a backplane constitutes one of the impediments to achieving low BERs. When a signal is transmitted over one channel, the current in a particular trace on the circuit board may induce an electromotive force (EMF) on neighboring traces, which is commonly referred to as crosstalk. The higher the frequency of a signal on one channel, the greater the noise induced on the other channel. Thus, a “victim” receiver on a particular channel receives, simultaneously, the signal intended to be received from a transmitter coupled to that channel as well as additional noise from one or more other crosstalk channels. Consequently, crosstalk cancellation becomes increasingly attractive as a means to increase the data rate of these devices. Thus, there is a need for addressing this issue and/or other issues associated with the prior art.